Stiffness of Retinal and Choroidal Tissue: A Surface Wrinkling Analysis of Epiretinal Membranes and Choroidal Folds
Accepted 4 April 2006. published online 23 May 2006.
Purpose
To measure the wrinkling periodicity (peak-to-peak or trough-to-trough distance) for epiretinal membranes and contraction-induced choroidal folds, and use this data to infer differences in the elastic properties of the retina and choroid, respectively.
Design
Retrospective case review.
Methods
Forty eyes were identified with epiretinal membranes (33 eyes) or contraction-induced choroidal folds (seven eyes). Digital red-free photographs were used to determine the average peak-to-peak distance between adjacent folds of retina or choroid using commercially available software.
Results
The average peak-to-peak spacing was considerably larger for contraction-induced choroidal folds vs retinal folds caused by epiretinal membranes (278.2 ± 62.2 vs 82.2 ± 7.66 μm, respectively; P = .0001). There was no statistically significant correlation between the peak-to-peak distance and patient age for the epiretinal membrane group (P = .25) or the choroidal folds group, although the age range of patients within the later group was narrow.
Conclusions
Epiretinal membranes and contraction-induced choroidal folds are two examples of wrinkling of biologic tissue under tangential stress. The larger peak-to-peak spacing for choroidal folds vs retinal folds demonstrates that the choroid is considerably stiffer than the retina under mechanical deformations.
aDepartment of Ophthalmology, Columbia University, New York, New York
bVitreous-Retina-Macula Consultants of New York, New York, New York.
Inquiries to Lucian V. Del Priore, MD, PhD, Professor and Robert L. Burch III Scholar, Department of Ophthalmology, Harkness Eye Institute of Columbia University, 635 West 165th Street, New York, New York
Supported in part by the Eye Surgery Fund, Robert L. Burch III Fund, the Macula Foundation, the Hickey Foundation, and Research to Prevent Blindness, Inc, New York, New York.
ABSTRACT